Results from the first funding period have demonstrated conclusively that dietary taurine is essential for normal feline pregnancy and outcome, and that its absence from the diet results in excessive reproductive wastage and a number of neurological abnormalities in surviving offspring. So far we have documented morphological abnormalities in the cerebellum, visual cortex, retina and tapetum of 8-week-old kittens accompanied by reduced taurine concentrations. In addition to the conventional qualitative histological and electron microscopical evaluation of morphological abnormalities in the offspring resulting from maternal dietary taurine depletion, we propose to make quantitative measurements in some nervous system tissues, e.g. to determine the number of cerebellar granule cells which reach the internal layer and the number of neurons in a column of visual cortex. Such quantitative studies will be especially important for the evaluation of marginal taurine deficiency. We propose to continue and extend the present investigations to include other regions of the nervous system and we have preliminary evidence of spinal cord abnormalities which may be related to the scoliosis observed in these kittens and may shed some light on the problems of Freidreich's Ataxia which shares many of the same neurological abnormalities and is associated with increased taurine excretion. We propose to study the effects of long-term taurine deficiency including the study of rehabilitation by post weaning taurine consumption to examine the possibility of reversal or amelioration of any of the abnormalities. Even though such important events as migration and differentiation are unlikely to be changed by such treatment, arborization and synapse formation may be aided. Another important aspect of the proposed research is the study of feline pregnancy and outcome of the progeny with marginal maternal taurine deficiency by the use of graded amounts of taurine in the diet. Use of a totally taurine-free diet produces extreme abnormalities in nervous system development so it is crucial to examine dietary taurine requirement by these more sophisticated parameters of morphological and biochemical status of the progeny. Finally, we propose to examine the degree to which the changes can be averted or ameliorated by maternal dietary intervention, both during pregnancy and during lactation. The importance of these studies to the human situations of pregnancy during malnutrition and pregnancy of vegans or partial vegans who consume little or no taurine is evident.